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Jan. 24,1956 E. T. BOOTH 2,732,127

DIAPHRAGM PUMP Filed Feb. 13, 1943 3 Sheets-Sheet l .LLI I II ulnnllnnnnn Illllllllllll 1111 I I] III] LA I 11!!!! 1/ IIIIII/I I II II IN! 'ENTOR.

Eugene T. Booth Jan. 24, 1956 BOQTH 2,732,127

DIAPHRAGM PUMP Filed Feb. 13, 1943 3 Sheets-Sheet 2 Fig.2

IN V EN TOR.

Eugene T. Booth Jan. 24, 1956, E. T. BOOTH 2,732,127

DIAPHRAGM PUMP Filed Feb. 13, 1943 3 Sheets-Sheet 3 1 Fig.5

IN V EN TOR.

Eugene T. Booth United States Patent DIAPHRAGM PUMP Eugene T. Booth, New York, N. Y., assignor to the United States of America as represented by the United States Atomic Energy Commission Application February 13, 1943, Serial No. 475,845

1 Claim. (Cl. 230-162) This invention relates to a diaphragm pump and more particularly to an all-metal diaphragm pump operated by pulsating gas pressure.

The invention is especially adapted for use in connection with the separation of uranium isotopes by diffusion of gaseous uranium hexa-fluoride (UFe) where the entire portion of the pump exposed to the uranium hexafiuoride gas must resist corrosition by this gas to a very high degree. Not only must corrosion in amounts injurious to the mechanical operation of the pump be avoided but successful operation of the isotope separation cascade requires a net loss of uranium hexa-fiuoride of less than 1 part of gas for every parts of gas passing through the pump. For this reason, all ordinary lubricants must be excluded from the pump. The best materials for use in the construction of such a pump appear at present to be nickel, copper, brass, aluminum, stainless steel, K-Monel and the noble elements. Other materials may be found to have the necessary corrosion resistance, although at present an all-metal construction seems necessary. It is not however intended to limit the materials used to those herein enumerated.

Although dry air is inert to uranium hexa-fluoride gas any sizable leaks of air into the system through the pumps cannot be tolerated, especially air with appreciable moisture content. It is believed that efiicient operation of the cascade requires that pressures and flows be maintained within a few percent of a determined value for the average run of the system lasting preferably several months if not longer. This means that there is a high premium upon an absolutely tight sealed system and that any leaks must be extremely small and uniform in order that operating conditions can be arranged to meet them.

The equilibrium time of the diffusion plant being dependent largely upon the ratio of the volume of the unit of the cascade and the pumping speed of that unit, pumps operating at frequencies of 1000 reciprocations per minute or faster are necessary.

The primary purpose of the persent invention is to pneumatically operate a diaphragm pump especially designed to be used in pumping gases in a difr'usion system. A feature of the invention is to provide an all-metal pump which resists corrosion by the action of the gases to a high degree.

Another feature is the novel means for pneumatically actuating the pump diaphragm and the elimination of ordinary lubricants from the pump.

Among still further features of the invention is the provision of a pump with a minimum leakage over a long period of high speed operation and of a character which is relatively simple, rugged in design and compact. Other features and advantages of the invention will, moreover, hereinafter more fully appear. 7

It has been known that one of the chief difliculties of pumps used in pumping gases in diffusion systems is the corrosion of the parts after a relatively short operative life and the resultant breakdown and interruption in the operation of the system. The construction of the pump and the manner in which such objects and other are attained and the foregoing difiiculties met, as well as the general scope of the invention will be more fully understood from the following detailed description considered with reference to the accompanying drawings.

Fig. 1 is a vertical sectional view of one illustrative embodiment of the invention;

Fig. 2 is a vertical sectional view along line 2-2 of Fig. 1 with parts broken away;

Fig. 3 is a horizontal cross-section along line 33 of Fig. 1;

Fig. 4 is a detailed sectional enlarged view of the pumping parts showing a variation in the form of the diaphragm.

Fig. 5 is a detailed sectional view along line 5-5 of Fig. 4;

Fig. 6 is a detailed sectional view of the cone valve; and

Fig. 7 is an enlarged view of the grating of the lower disc along line 7-7 of Fig. 4 with part of the disc broken away.

In the specific embodiment of the invention shown in Figs. 1 to 7, inclusive, the numeral 1 designates a thin, flexible metal diaphragm preferably made of berylliumcopper, nickel, stainless steel, the noble elements or other metals or alloys which have a high fatigue value and are corrosive resistant. The diaphragm is of a thickness of the order of four thousandths (0.004) of an inch. The

thickness of the diaphragm varies within an operable,

range depending on the size and shape of the pump. The surface of the diaphragm may be formed to follow the contours of the metal discs 2 and 3 or may be preformed to any given shape to increase the etficiency of the pump and operating life of the diaphragm.

The preformed diaphragm 1 of suitable size and shape is soldered or clamped by nuts and bolts or secured by any other suitable clamping and sealing means, between two pre-shaped concave metal discs 2 and 3 which when clamped together form the chamber 4. The movement of the diaphragm 1 is limited by the curvature of the discs 2 and 3 of chamber 4. The chamber 4 is divided by the diaphragm into two compartments, the upper flexible diaphragm compartment 5 and the lower flexible diaphragm compartment 6, constituting pumping and actuating cornpartments, respectively. The metal diaphragm is caused to vibrate by the lower compartment 6 being alternately connected to a first source of pressure and an independent second source of pressure that is less than the first source, such as, for example, an air supply and exhaust means, through conduit 7 and a grating 8 consisting of a number of holes bored in the lower disc 3 which are of the order of magnitude of approximately inch in diameter, closely packed into a circumference approximately the width of the conduit 7. The grating, more clearly shown in Fig. 7, prevents the diaphragm from deforming due to suction created during the exhaustion of the air from the lower air compartment 6.

The air supply and exhaust means may comprise any suitable type of valve or valves which alternately connects the lower compartment 6 to a source of air supply preferably under pressure and then to air exhaust means. The type of valve shown in Figs. 1, 2 and 6 is a metal cone Valve 9 encased in a sealed casing 10 connected on top to the conduit 7 and on the bottom to air supply line 22 and vacuum line 23. The cone valve 9 may be made of brass, nickel, steel or any other suitable metal and horizontally mounted on any suitable bearings positioned at the respective ends of the cone so as to permit free rotation of the cone within the casing when. driven by any external means.

As seen in Fig. 6, a single ball bearing 11 is pivoted in a raceway formed by a V-shaped bearing edge 12 in the end of the cone with a V-shaped bearing edge 14 of spring supported block 13. The block 13 being loose- 1y fitted into screw block 1.5 and held in position by spring 16 which is of sufiicient resilience to keep the cone in place during the rotation thereof. At the opposite end of the cone 9 is afiixed a shaft 17, which extends through. a block 19' fitted over. the end of the casing 10, and which is driven by a motor M and pulley 17a. The shaft. 1.? is supported between ball thrust bearings 18'-18 held in block 19 to prevent the cone from seizing under the stress of operating at high speeds.

In the position shown in Fig. l the vacuum line 2: is connected to the lower diaphragm chamber 6 and conduit 7 by slot 20-26 as seen more clearly in Fig. 2. A 90 turn of the cone isolates the vacuum line 23 and connects the air or. other gas pressure line 22 through the smaller. slot 21-21 to conduit 7 and the diaphragm chamber 6. Thus for every 90 rotation of the cone,

air or other gas is alternately admitted and exhaustedfrom the lower diaphragm chamber 6 and the conduit 7 so that if the cone rotates at aspeed'of 500 revolutions per minute. the diaphragm makes 1000 vibrations per minute. That is to say that the diaphragm vibrates twice as fast as the cone. rotates. The size of the slots varies with the size and shape of the pump as well as the particular speed at which the pump is to operate. However, the exhaust slot should be larger than the intake slot. Under certain circumstances it might be advantageous to use hydrogen or helium, or another of the inert gases lighter than uranium hexa-fluoride. The air or gas intake line 22 communicates with bufler tank 24 which is connected to any suitable type of air or other gas pressure pump, designated 39. The vacuum line 23 communicates with a buffer tank 25 which leads to a vacuum pump 49 capable of maintaining a pressure about one-half pound. per square inch lower than the minimum pressure of the gas being pumped. The pressure intake tank 24 should be maintained at a pressure a few pounds per square inch in excess of the maximum pressure to which the working gas is to be pumped. I the latter is below atmospheric pressure the tank 24 can be opened to the atmosphere or even connected to a throttle valve to maintain the pressure a few pounds above the maximum pressure of the gas being umped. Thus, the practical operating conditions for the pump are satisfied by providing a first pressure source sufiieient to actuate the diaphragm against the casing member 2 and pump the working gas from the compartr-icnt 5, and a second pressure source that is less than the first and effects rapid actuation of the diaphragm to its opposite position against the casing member 3.

The upper flexible diaphragm compartment admits and discharges the gases or vapors due to the vibration of the diaphragm 1 and the valve action of. intake valve 26 and outlet. valve 27; Any suitable type of valve may be used; However, without limiting the invention to any specific type, a reed type is shown in Figs. 1, 2, 4 and 5 in which each valve consists of a leaf 28 or 29 of 0.10 inch of Phosphor bronze fastened at one end asshown in Fig. 2 by clamps or screws 3%. Each leaf 28 and 29 covers its respective rectangular slot 32' and 31 which are 1 inch wide by 1% inches long. The particular size and shape not being critical to the operation, any proportionate adaptable size and shape may beemployed. The leaves 28 and 29 overlap the respective sides and end of the rectangular openings so as to completely close the openings at their respective operable times. The leaf 2s of intake valve 26 is fastened by suitable means to the backing strip 33 of. brass: or other suitable. metal on the side nearest the diaphragm which limits the maximum opening of the valve at the free end to approximately ,4; inch when gasenters diaphragm chamber 5. The leaf 23 of. exhaust valve 27 is similarly fastened bysuitable. meansto asimilar backing strip 34 on the side. remote t'ron the diaphragm which similar- 1y limits the maximum opening of that valve at the free end to about /8" inch when gas is being forced into the passage 35 out of chamber 5.

The openings to the upper flexible diaphragm chamber 5 are, in the case of both intake and exhaust passages 35 and 36, through a series of small closely packed holes bored in the upper concavev disc. 2 forming intake grating 37 and outlet grating 38. These gratings prevent the vibrating diaphragm from deforming due to any suction created by the opening and closing of the valves 26 or 27. The gratings. prevent the diaphragm from deforming at the valve openings during operation.

The passages 35 and 36 are connected and sealed to their respective valve openings and lead to a cascade diffusion system (not shown) in which the gas or vapor, in this instance uranium hexa-fiuoridc, is fed into intake passage 35 and pumped out into exhaust passage 36 by reason of the diaphragm. vibrations actuating the re spective intake and exhaust valves;

The clamping, sealing and connecting means whether by bolts, rivets, welding or other means is notmaterial to the invention as long as a sealed unit in which the loss of gas is, as hereinb'efore stated, to be very minute, that is of the order of 1' unit to 10 units of gas pumped andi'n which there is no or very little infiltration of air into the diffusion system through the pump. Thus it is extremely important that the metal diaphragm and metal pumping system be absolutely tightly sealed.

it' should be understood that for economical operation the air or gas pressure pump 39, the vacuum pump as and the motor to drive the cone valve are of such a character that they are capable of continued operation for periods in excess of six months.

in the position of operation shown in Fig. 1 the vacuum pump has just exhausted the air or gas through slot 2020'in operative relation with exhaust line 23 from the lower flexible diaphragm chamber 6 and conduit 7, gas'has just entered the upper flexible diaphragm chamber 5, leaf 29 of reed valve 26 has just closed by reason of the pressure in the upper diaphragm chamber 5 equalizing the gas pressurein passage 35, leaf 28 of reed valve 27 is still closed but ready'to instantaneously open and force the gasin chamber'S into the diffusion system through passage 36 and the diaphragm has reached its maximum downward flex. Upon the rotation of the cone valve, slot 20-26 is brought out of operative relation with vacuum line 23 and conduit 7. When the valve has rotated the air or gas slot 2121 is brought into operative relation with air or gas line 22 and air or gas is forced from buffer tank 24 by pressure pump 39 into line 22 through slot 21'21 into conduit 7 and the lower flexible diaphragm chamber 6 through grat' ing 8 in disc 3. Air or gas entering the lower flexible diaphragm chamber 6-causes the diaphragm to move upward forcing the gas in' the upper flexible diaphragm chamber 5 to open leaf 28 of valve 27 against its backing block 34 to discharge gas through outlet passage 36 to the diffusion system until the flexible diaphragm reaches the maximum upward flex; During all this time leaf 29 is pressed against the edges 4 and 42 of opening 31 preventing any gas'from flowing back into passage 35. Upon the motor rotating the cone valve again, slot 21..21 i'sbrought' out of' operative relation with the air or'gas supply line and upon completion of another 90 rotation the slot" 2020 is brought into operative relation with vacuum line 23 and conduit 7. The air or gas is then sucked out of lower diaphragm chamber 6 and the conduit 7 causing the diaphragm i to return to the position shown. in Fig. 1. As the diaphragm moves downward the leaf 29 of reed valve 26 opens againstiblock. 33 and gas. in the intake passage 3 rushesinto the upper flexible diaphragm chamber 5. At the same time. leaf 28- of reed valve 27 is closed by the suction,v and. when the diaphragm. has reached its maximum downward flex a complete. cycle of operation in 180 rotation of the cone valve will have taken place. It is readily appreciated that as two complete cycles of operation take place with a complete 360 revolution of the cone valve shaft, that the operation takes place in a fraction of a second when the motor is operating at 500 revolutions per minute.

It will be appreciated that the embodiment provides a comparatively simple construction of a high speed pump and, while especially adapted to the particular field of separation of uranium isotopes by the diffusion of gases it is also of general application.

While the invention has been described in a form which it may assume in practice it will be apparent that the invention is not restricted to the construction shown and that various modifications may be made within the scope of the invention and embodied in various other forms without departing from its spirit or the scope as set forth in the claims.

I claim:

In combination, means defining a pumping chamber and an actuating chamber including a casing and a thin metal diaphragm between said chambers, a first source of positive pressure, a second independent source of suction pressure less than said first source, valve means operable to connect said actuating chamber alternately with said first and second pressure sources to reciprocably vibrate said diaphragm in a positive manner in respectively opposite directions, and means in said casing operable to alternately admit and discharge a fluid from said pumping chamber upon each reciprocal vibration of the diaphragm, said means comprising an inlet and an outlet valve in said casing each having a flexible reed closure member and means operable to limit maximum opening of said reed with respect to said valve.

References Cited in the file of this patent UNITED STATES PATENTS 225,930 Hostel Mar. 30, 1880 1,101,266 Franklin June 23, 1914 1,262,665 Hedges Apr. 16, 1918 1,623,605 Tainton Apr. 5, 1927 1,707,319 Risberg Apr. 2, 1929 1,995,611 Hapgood Mar. 26, 1935 2,142,329 Nika et a1. Jan. 3, 1939 FOREIGN PATENTS 33,603 Denmark 1924 122,834 Austria 1934 295,913 Great Britain 1928 

